My client needs to use an android cellphone as an asterisk channel/Gateway. His aim is to make phone calls using his Asterisk PBX through a cellphone running android.
You are free to choose how to implement this feature. All that is required is that in the end the Android phone will be acting as a SIP or IAX to GSM channel/trunk/FXO and other SIP devices can connect and make phone calls using this.
You choose the best way to do it:
Add the feature to SIPDroid: [url removed, login to view]
Add the feature using the BatPhone Asterisk Build: [url removed, login to view]
Or do it your own way.